An inlet end piece of this type has, for example, a pipe inlet and a closure insert arranged in the upper area of the pipe inlet, for closing the pipe inlet in relation to the environment. The closure insert preferably has a filling opening for introducing the filler pipe of a gas pump nozzle and a sealing flap pivotable about a pivot axis, which in particular can be opened by pivoting counter to the force of a closing force that counteracts the opening movement by the filler pipe when the latter is being inserted. This closing force is preferably formed by a closure spring that is tensioned by opening the closure flap. In the closed state of the closure flap, the closing force holds the closure flap so as to bear on a detent which is formed in particular by a seal.
An inlet end piece of this type is known from DE 10 2010 036 970 A1. This herein is a so-called lid-free inlet end piece which has an upper protection mechanism against erroneous fueling and the lower sealing flap that is disposed at a spacing from said protection mechanism. These lid-free inlet end pieces have the advantage that they can prevent both an erroneous refueling of a diesel vehicle with gasoline, as well as conversely an erroneous refueling of a vehicle having a gasoline engine with diesel fuel. However, the applicability of the present invention is not limited to this special aspect or to a lid-free inlet end piece.
On account of the sealing flap in the case of the known inlet end piece being disposed so as to be spaced apart from the upper entry flap of the protection mechanism, the user either when pulling the gas pump nozzle out of the inlet end piece, or else by way of an insufficient introduction depth, can fill a minor quantity of fuel into the area between the sealing flap and the upper protection mechanism. Said fuel by way of a discharge line then runs out of this upper area.